Methods and apparatus for treating embolism

ABSTRACT

A method and apparatus for treating a clot in the blood vessel of a patient, and particularly the treatment of a pulmonary embolism is disclosed. The treatment includes restoring flow through the clot followed by clot removal, either partially or substantially completely. The clot treatment device is expandable into the blood vessel and may contain radial extensions that assist in restoring flow as well as in removing clot material.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.15/949,350, filed on Apr. 10, 2018 and entitled Methods and Apparatusfor Treating Embolism, which is a continuation of U.S. patentapplication Ser. No. 14/646,358, filed on May 20, 2015, now issued asU.S. Pat. No. 10,004,531, and entitled Methods and Apparatus forTreating Embolism, which is a 371 U.S. national filing ofPCT/US2013/071101, filed on Nov. 20, 2013, and entitled Methods andApparatus for Treating Embolism, which is a continuation-in-part of U.S.patent application Ser. No. 13/843,742, filed on Mar. 15, 2013, nowissued as U.S. Pat. No. 8,784,434 and entitled Methods and Apparatus forTreating Embolism, which claims priority to U.S. Provisional ApplicationSer. No. 61/750,277 filed Jan. 8, 2013 entitled Devices and Methods forTreatment of Vascular Occlusion and U.S. Provisional Application Ser.No. 61/728,775 filed Nov. 20, 2012 entitled Devices and Methods forTreatment of Vascular Occlusion, all of which are hereby incorporatedherein by reference in their entireties.

TECHNICAL FIELD

This invention relates to the apparatus and methods of endovasculartreatment of blood clots obstructing passageways in the circulatorysystem and particularly the endovascular treatment of pulmonaryembolism.

BACKGROUND

Thromboembolism is the formation in a blood vessel of a clot (thrombus)that breaks loose (embolizes) and is carried by the blood stream toanother location in the circulatory system resulting in a clot orobstruction at that new location. For example, a clot may embolize andplug a vessel in the lungs (pulmonary embolism), the brain (stroke), thegastrointestinal tract, the kidneys, or the legs. Thromboembolism is asignificant cause of morbidity (disease) and mortality (death),especially in adults.

A thromboembolism can be sudden and massive or it may be small andmultiple. A thromboembolism can be any size and a thromboembolic eventcan happen at any time.

When a thrombus forms in the venous circulation of the body it oftenembolizes to the lungs. Such a thrombus typically embolizes from theveins of the legs, pelvis, or inferior vena cava and travels to theright heart cavities and then into the pulmonary arteries thus resultingin a pulmonary embolism.

A pulmonary embolism results in right heart failure and decreased bloodflow through the lungs with subsequent decreased oxygenation of thelungs, heart and the rest of the body. More specifically, when such athrombus enters the pulmonary arteries, obstruction and spasm of thedifferent arteries of the lung occurs which further decreases blood flowand gaseous exchange through the lung tissue resulting in pulmonaryedema. All of these factors decrease the oxygen in the blood in the leftheart. As a result, the oxygenated blood supplied by the coronaryarteries to the musculature of both the left and right heart isinsufficient for proper contractions of the muscle which furtherdecreases the entire oxygenated blood flow to the rest of the body. Thisoften leads to heart dysfunction and specifically right ventricledysfunction.

This condition is relatively common and has many causes. Some of themore common causes are prolonged inactivity such as bed rest, extendedsitting (e.g., lengthy aircraft travel), dehydration, extensive surgeryor protracted disease. Almost all of these causes are characterized bythe blood of the inferior peripheral major circulatory systemcoagulating to varying degrees and resulting in permanent drainageproblems.

There exist a number of approaches to treating thromboembolism andparticularly pulmonary embolism. Some of those approaches include theuse of anticoagulants, thrombolytics and endovascular attempts atremoval of the emboli from the pulmonary artery. The endovascularattempts often rely on catheterization of the affected vessels andapplication of chemical or mechanical agents or both to disintegrate theclot. Invasive surgical intervention in which the emboli is removed byaccessing the chest cavity, opening the embolized pulmonary arteryand/or its branches and removing the clot is also possible.

The prior approaches to treatment, however, are lacking. For example,the use of agents such as anticoagulants and/or thrombolytics to reduceor remove a pulmonary embolism typically takes a prolonged period oftime, e.g., hours and even days, before the treatment is effective. Insome instances, such agents can cause hemorrhage in a patient. Moreover,the known mechanical devices for removing an embolism are typicallyhighly complex, prone to cause undue trauma to the vessel, and can bedifficult and expensive to manufacture.

Lastly, the known treatment methods do not emphasize sufficiently thegoal of urgently restoring blood flow through the thrombus once thethrombus has been identified. In other words, the known methods focusprimarily and firstly on overall clot reduction and removal instead offirst focusing on relief of the acute blockage condition followed thenby the goal of clot reduction and removal. Hence, known methods are notproviding optimal patient care, particularly as such care relates totreatment of a pulmonary embolism.

SUMMARY

In view of the foregoing, several embodiments of the present technologyto provide a method and system that initially restores an acceptablelevel of oxygenated blood to the patient's circulatory system followedby safe and effective removal of the thrombus.

Several embodiments of the present technology treat pulmonary embolismin a minimally invasive manner.

Several embodiments of the present technology can also provide a systemthat does not cause undue trauma to the vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, aspects, features and advantages of which thepresent technology is capable will be apparent from the followingdescription of embodiments of the present technology, reference beingmade to the accompanying drawings, in which

FIG. 1A is a schematic view of a patient with a pulmonary embolism;

FIG. 1B is an enlarged view of the lung area of the patient depicted inFIG. 1A;

FIG. 1C is an enlarged view of the introducer device depicted being usedin the femoral vein of the patient in FIG. 1A;

FIG. 2 is a cross-sectional view of a patient's heart;

FIG. 3 is a perspective view of a patient's main pulmonary artery andright and left pulmonary arteries with a clot located in the leftpulmonary artery;

FIG. 4 is a cross-sectional view of an embodiment of a clot treatmentdevice in accordance with the present technology in a compressed,undeployed state;

FIG. 5A is a side cross-sectional view of a clot treatment device in acompressed, undeployed state within a delivery catheter in accordancewith the present technology;

FIG. 58 is a top view of a clot treatment device in a deployed state inaccordance with the present technology;

FIGS. 6A-6F are a series of cross-sectional views of embodiments of themethod and device of the present technology;

FIGS. 7A-7B are a series of cross-sectional views of embodiments of themethod and device of the present technology;

FIG. 8 is a cross-sectional view of another embodiment of the method anddevice of the present technology; and,

FIGS. 9A-9H show cross-sectional views of embodiments of a clottreatment device in accordance with the present technology.

FIG. 10 is a cross-sectional view of a clot treatment device inaccordance with another embodiment of the present technology.

FIGS. 11 and 12 are detailed cross-sectional views of a distal portionand a proximal portion, respectively, of an expandable member of a clottreatment device in accordance with an embodiment of the presenttechnology.

FIGS. 13 and 14 are detailed cross-sectional views of a proximal portionand a distal portion, respectively, of an expandable member of a clottreatment device in accordance with another embodiment of thetechnology.

FIGS. 15-18 are side views of guide catheters for use with clottreatment devices and methods in accordance with embodiments of thepresent technology.

FIG. 19 is a side view of a clot treatment device including arcuate clotengagement members configured in accordance with an embodiment of thepresent technology.

FIGS. 20-23 show embodiments of arcuate clot engagement membersconfigured in accordance with the present technology.

FIGS. 24-25 are side views of clot treatment devices configured inaccordance with embodiments of the present technology.

FIG. 26 is a circumferential structure including arcuate clot engagementmembers in accordance with embodiments of the present technology.

FIG. 27 is a side view of a clot treatment device having a distalradially extending member configured in accordance with anotherembodiment of the present technology.

DETAILED DESCRIPTION

Specific embodiments of the present technology will now be describedwith reference to the accompanying drawings. This present technologymay, however, be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present technology tothose skilled in the art. The terminology used in the detaileddescription of the embodiments illustrated in the accompanying drawingsis not intended to be limiting of the present technology. In thedrawings, like numbers refer to like elements.

Referring to FIGS. 1A-1C, these drawings show the typical locations in ahuman patient where clots 100, such as pulmonary embolisms, thromboses,or other obstructions, occur in the pulmonary arteries and furtherdiscloses the pathway through which access to such clots 100 isachieved. In particular, an introducer device (e.g., a hemostatic valve)102 which supports relatively large diameter devices is inserted intothe patient into the femoral vein FV in the pelvic area of the patient.The tools and devices needed to treat the pulmonary embolism are theninserted through the introducer 102 into the femoral vein FV through theinferior vena cava IVC to the patient's heart.

It will be understood, however, that other access locations into thevenous circulatory system of a patient are possible and which areconsistent with the present technology. For example, the user can gainaccess through the jugular vein, the subclavian vein, the brachial veinor any other vein that connects or eventually leads to the superior venacava. Use of other vessels that are closer to right atrium RA of thepatient's heart may be attractive as this will reduce the length of theinstruments needed to reach the pulmonary embolism.

Referring to FIGS. 2 and 3, the tools/devices are then guided throughthe right atrium RA through the tricuspid valve TV, into the rightventricle RV, through the pulmonary valve PV into the main pulmonaryartery (MPA). Depending on the location of the embolism 100, thetools/devices are then guided to one or more of the branches of theright pulmonary artery RPA or the left pulmonary artery LPA, includingdeeper branches thereof, to the location of the pulmonary embolism 100.

Referring to FIG. 4, an embodiment of a clot treatment device 402 forrestoring blood flow through the clot 100 and for removing at least aportion of the clot is depicted in its undeployed, or compressed state.The device 402 is constrained by a delivery catheter 606. In manyembodiments, the device 402 comprises a braided material having endsthat are captured distally by a tip 405 and proximally by an attachmentmember 403 that connects to a wire 401 configured to push and/or pullthe clot treatment device 402.

In alternative embodiments, the clot treatment device 402 may be an“over the wire” device, in which case, the wire 401 is a tube or coilhaving a lumen, and the attachment member 403 and the tip 405 have ahollow central lumen for receiving a guide wire.

In yet a further embodiment, the distal end of the clot treatment deviceshall have a flexible, atraumatic extension from the device. In analternative embodiment, the tip 405 is tapered to better penetrate theclot material in the vessel.

In preferred embodiments the clot treatment device 402 of the presenttechnology has a generally cylindrical shape that, during use, creates aflow lumen through the clot material that restores significant bloodflow across a clot. The treatment device 402 is not, however, limited toa generally cylindrical shape. For example, the shape can be generallyconical, generally concave or generally convex along its axis such thatthe clot treatment device 402 creates a lumen for restoring the bloodflow.

FIG. 5A shows one embodiment of the treatment device 402 in alow-profile, undeployed state in which the clot treatment device isconfigured to fit within a delivery catheter, and FIG. 58 shows the clottreatment device 402 of FIG. 5A in a deployed state configured torestore blood flow and capture clot material for removal. Referring toFIG. 5A, the clot treatment device 402 is compressed to fit within thediameter OL of a lumen 607 of the delivery catheter 606 in theundeployed state. In the deployed state shown in FIG. 58, the clottreatment device 402 has a plurality of capture elements, such as aseries of radially extending capture portions 406 which are separatedfrom each other by flow restoration portions 412. The flow restorationportions 412 are configured to expand outwardly from the low-profileundeployed state within the delivery catheter lumen 607 to a firstcross-sectional dimension 01 (e.g., diameter) in the deployed state. Forexample, the flow restoration portions 412 can be generally cylindricalbraided sections that expand radially outward from the undeployed statedto the deployed state. In many applications, the first cross-sectionaldimension 01 is greater than the diameter OL of the delivery catheterlumen 607. The capture portions 406 are configured to expand outwardlyfrom the low-profile undeployed state to a second cross-sectionaldimension 02 greater than the first cross-sectional dimension 01 in thedeployed state. As explained in more detail below, the capture portions406 can project into the clot such that they extend transverse to alongitudinal axis L-L of the clot treatment device 402, while the flowrestoration portions 412 expand radially outward into the clot to open apassage through which blood can quickly resume flow through the vessel.The clot treatment device 402 can be porous so blood flows therethrough.In this regard, many embodiments of the clot treatment device 402 aremade from a mesh or braided material. The material can be asuper-elastic material such as Nitinol or an alternative material suchas cobalt chrome alloy. The device can be made from a wire lattice, wirebraid or stent. Specific preferred embodiments are discussed throughoutthis specification.

Referring again to FIG. 58, the clot treatment device 402 can comprise asingle mesh structure that is generally cylindrical in the low-profileundeployed state (shown in FIG. 5A). The series of radially extendingcapture portions 406 accordingly extend from the same mesh as thecorresponding series of flow restoration portions 412. The flowrestoration portions 412 can be generally cylindrical sections in thedeployed state, or in other embodiments the flow restoration portions412 may taper in the distal direction individually and/or collectivelyto form a conical lumen (not shown). Each of the capture portions 406can be a radial or otherwise transversely projecting disk that projectsoutward relative to the flow restoration portions 412.

The clot treatment device 402 can self-expand from the undeployed stateto the deployed state. For example, the clot treatment device 402 can bea shape-memory material, such as Nitinol, and may be formed as a braidor a stent that is set to have the expanded configuration of thedeployed state shown in FIG. 58 unless it is otherwise deformed orconstrained, such as being elongated along the longitudinal axis L-L tofit within the delivery catheter 606 as shown in FIG. 5A. In otherembodiments, the clot treatment device 402 can be actuated by apush/pull wire, tube or coil to move from the low-profile undeployedstate to the expanded deployed state as explained in more detail belowwith reference to FIGS. 10-12.

FIGS. 1-6F show embodiments of methods for restoring blood flow andretrieving/removing clot material with the clot treatment device 402 ina body lumen L.

Referring to FIGS. 1A, 1B and 6A, a guide wire 602 is inserted into thepatient via an introducer 102 and maneuvered through the femoral vein FVinto the inferior vena cava IVC to the heart. As stated above, accesscan also be achieved through one of the veins leading to the superiorvena cava SVC. The guide wire 602 is then urged through the right atriumRA, through the tricuspid valve TV, through the right ventricle RV,through the pulmonary valve PV to the main pulmonary artery MPA and thento a location of the clot 100 in one of the branches or lumens L ofeither the right or left pulmonary artery RPA, LPA. In severalembodiments, the guide wire 602 is extended through the clot 100 in thebody lumen Las shown in FIG. 6A.

Referring to FIG. 68, a guide catheter 604 is placed over the guide wire602 and moved to a location where a distal end of the guide catheter 604is positioned proximal to the clot 100. At this point, the guide wirecan optionally be withdrawn. However, in the embodiment shown in FIG.6C, the guide wire 602 remains positioned through the clot 100 and adelivery catheter 606 is then moved through the. guide catheter 604 overthe guide wire 602 and pushed through the clot 100.

Referring to FIG. 60, the guide wire 602 is then withdrawn and the clottreatment device 402 in its undeployed (i.e., compressed) state is thenmoved through the delivery catheter 606 until it is positioned at thedistal end of the delivery catheter 606. Alternatively, if anover-the-wire device configuration (as shown in FIG. 10) is used, theguide wire 602 may be left in place while the treatment device 402 isdeployed and retracted. Referring to FIG. 6E, the delivery catheter 606is then retracted in a proximal direction while maintaining forwardpressure on the clot retrieval device 402 via the pusher wire 401 sothat the clot treatment device 402 is exposed and released from thedelivery catheter 606. The clot treatment device 402 radially expandsinto the clot 100 and, in some embodiments, at least a portion of theclot treatment device 402 expands distal of the clot 100. For example,at least one of the radially extending capture portions 406 of the clottreatment device 402 is located distal to the clot 100 upon expansion ofthe clot treatment device 402. Additionally, the flow restorationportions 412 between the capture portions 406 also expand outwardlyagainst a portion of the clot 100 to form a flow passage 430 though theclot treatment device 402.

The clot treatment device 402 accordingly restores blood flow throughthe clot 100 immediately or at least quickly after expanding to thedeployed state as shown by arrows 407 in FIG. 6E. More specifically, theblood freely moves through the mesh of the clot treatment device 402,travels through the device lumen and exits the clot treatment device 402distal to the clot 100. As a result, the acute condition of blockage ismediated thus immediately improving the circulation of oxygenated bloodin the patient.

The restoration of blood flow is anticipated to equate with restorationof a substantial portion of the normal blood flow rate for the patient.In less severe. e.g., “sub-massive,” pulmonary embolism patients, theclot treatment device 402 may increase blood flow rate by at least about50 ml|min, at least about 150 ml|min or between about 100 to 250 ml|min.In severe, e.g., “massive,” pulmonary embolism patients, a larger amountof the pulmonary artery flow is compromised. Hence, in some embodiments,at least about 500 ml/min of blood flow rate may be restored. Moreover,at least a portion of the flow restoration is expected to occur prior tothe removal of the clot 100, or any portion thereof.

The restoration of blood flow by the clot treatment device 402 can beachieved in a low pressure environment. For example, the pressure in thetarget vessel can be less than 60 mmHg and the blood can be venousblood, substantially non-oxygenated blood or low oxygenated blood.

In addition to restoring blood flow, the expansion of the clot treatmentdevice 402 also deforms the clot material by pushing, penetrating and/orotherwise cutting into the clot material. This enhances the subsequentremoval of the clot 100 since portions of the clot 100 may be capturedand retained (1) between the radially extending portions 406; (2)through the pores of the mesh forming the radially extending portions406; (3) along the longitudinal cylindrical sections 412 between theradially extending portions 406 of the removal device 402; and (4)within the clot treatment device 402 itself.

As can be understood from the above description and figures, thedeployment of the clot treatment device 402 results in an outwardlyexpanding generally cylindrical force being urged against an innersurface of the clot 100 because the flow restoration portions 412 expandto the first cross-sectional dimension D1 greater than the diameter DLof the delivery catheter lumen 607. This force pushes the clot materialoutwardly and creates a lumen through which blood flow is restored. Ascan also be appreciated, the presence of the radially extending captureportions 406 on the clot treatment device 402 causes the outwardlyexpanding generally cylindrical force to vary in magnitude along theaxis of the clot treatment device 402. The force on the clot materialmay be greater at the locations of the radially extending captureportions 406.

In braided embodiments of the clot treatment device 402,deployment/expansion of the device leads the filaments of the braid tochange their angular orientation with respect to the axis of the device.This angular change may improve or enhance adherence of clot material tothe clot treatment device 402.

After the clot treatment device 402 has been expanded and blood flowrestored, the user then retracts the clot treatment device 402 in aproximal direction as shown in FIG. 6F. Sinethe capture portions 406extend transverse to the longitudinal dimension of the vessel, thecapture portions 406 form transverse surfaces relative to the forceexerted against the clot 100 as the clot treatment device 402 is pulledin the proximal direction. The capture portions 406 accordingly enhancethe ability of the clot treatment device 402 to securely dislodge andretain the clot 100 as the clot treatment device 402 is moved axiallyalong the vessel to retrieve the clot 100 from the patient. In oneembodiment, the clot treatment device 402 and the delivery catheter 606are pulled back simultaneously into the guide catheter 604. This isfollowed by the entire apparatus (e.g., clot treatment device 402,delivery catheter 606 and guide catheter 604) being withdrawn throughthe heart and the venous circulation and out from the body.

As further shown in FIG. 6F, the clot treatment device 402 may elongateas it is being withdrawn into the guide catheter 604 due to theresistance it encounters from the presence of clot material of the clot100. The presence of the radially extending portions 406 may allowelongation that enhances the capability of the device 402 to capture themaximum amount of clot material. This is further discussed below withrespect to the surface area and expansion ratio of preferred embodimentsof the clot treatment device 402.

It will be appreciated that variations in the above-described method arecontemplated. For example, in certain circumstances a guide catheter 604may not be necessary or desirable and the user may choose to use onlythe delivery catheter 606 for placing and manipulation of the clottreatment device 402. As a further example, the clot may be of such anature that the user may desire repeat the above-described process, orat least portions of it, in order to more fully remove the clot 100 orclot material.

Referring next to FIGS. 7A-78, it may be advantageous to include the useof a collection or funnel catheter 612 to assist in the removal of theclot 100. Such a funnel catheter 612 has an expandable portion 614 atits distal end and may be situated between the guide catheter 604 andthe delivery catheter 608 or may be part of the guide catheter 604. Inthe presence of the collection catheter 612, the clot treatment device402 is pulled proximally into the collection catheter 612 such that theclot or portions of it are captured within the collection catheter 612.In an alternative embodiment, the collection catheter 612 can be pusheddistally over the clot treatment device 402 such that the collectioncatheter 612 captures the clot or portions thereof. If the collectioncatheter 612 is separate from the guide catheter 606, the collectioncatheter with the clot treatment device 402 is then pulled into theguide catheter for ultimate removal of all devices (and the clot) fromthe patient.

In certain circumstances, it may be advisable to remove the clot 100without capturing it in the guide catheter 606 or the collectioncatheter 612 (if used) and remove the clot 100 by withdrawing the entiresystem, e.g., guide catheter 605, delivery catheter 604, clot treatmentdevice 402 and collection catheter 612 (if used) simultaneously.

In several embodiments, the expandable portion 614 of the collectioncatheter 612 is a conical funnel or other tapered member constructedfrom a mesh, braid or stent structure. Such structure assists inretrieving and containing the clot material in the withdrawal process.In yet further preferred embodiments, the collection catheter 612contains structural features to assist in the expansion of theexpandable portion 614 and to hold the expandable portion 614 opentowards the wall of the blood vessel. Such features (not shown) includeinterwoven support struts, self expanding material (e.g., Nitinol),longitudinal wire supports, stent supports, polymeric webbing, etc.

In another embodiment of the present invention, a vacuum apparatus maybe used to aid in the removal of the clot material. Referring to FIG. 8,a syringe 802 is shown connected to a vacuum manifold 806 that is influid communication with the proximal end of the guide catheter 604. Atthe time the clot treatment device 402 (and clot material) is beingwithdrawn into the guide catheter 604 (or the collection catheter 612),vacuum is applied by pulling on the syringe. Alternative sources ofvacuum 804 are also acceptable, e.g., a vacuum pump. A system is alsocontemplated whereby vacuum is actuated automatically when the clottreatment device 402 (and the clot material) is being withdrawn. Arepresentation of the effect of the use of vacuum can be seen withreference to FIG. 78 which shows how vacuum causes flow 701 into thecatheter 612.

Referring now to FIGS. 9A-9H, alternative preferred embodiments of theclot treatment device 402 are disclosed.

Referring to FIG. 9A, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by a cylindrical disk shape with a rounded triangularcross-section.

Referring to FIG. 98, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by a cylindrical disk shape with a rounded triangularcross-section wherein the diameter of the disk increases along thelength of the device 402 thus forming a conical exterior extent.

Referring to FIG. 9C, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by a cylindrical disk shape with a rectangular cross-section.

Referring to FIG. 90, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by a cylindrical disk shape with a linear (non-rounded)triangular cross-section.

Referring to FIG. 9E, some of the radially extending portions 406between the generally cylindrical sections 412 of the clot treatmentdevice 402 are defined by a cylindrical disk shape with a roundedcross-section and others have a rectangular cross section.

Referring to FIG. 9F, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402alternate between cylindrical disk shape with aT-shaped cross-sectionand a flare-shaped cross-section.

Referring to FIG. 9G, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by a partial cylindrical disk shapes.

Referring to FIG. 9H, the radially extending portions 406 between thegenerally cylindrical sections 412 of the clot treatment device 402 aredefined by tabs and bumps or protuberances arising from the cylindricalsurface of the device 402.

FIG. 10 is a cross-sectional view of another embodiment of the clottreatment device 402 in accordance with the technology having anexpandable member 1010, an elongated inner member 1020, and an elongatedouter member 1022. The expandable member 1010 is configured to have anundeployed state in which the expandable member 1010 is elongatedaxially to have a low profile that fits within a delivery catheter asshown in FIG. 4. The expandable member 1010 is further configurable intoa deployed state in which the expandable member 1010 forms a flowchannel 1012 for restoring blood flow through the region obstructed bythe clot. The expandable member 1010, for example, can be a mesh, braid,stent-type device, or other suitable member through which blood flows inthe deployed state. In one embodiment, the expandable member 1010 is acontinuous braid formed from a shape-memory material that has been heatset such that, in the deployed state, the expandable member 1010 has aplurality of flow restoration portions 412 that expand to the firstcross-sectional dimension 01 to form the flow channel 1012 and aplurality of capture portions 406 that expand to the secondcross-section dimension 02 greater than the first cross-sectionaldimension 01. The flow restoration members 412 accordingly exert anoutward force (arrows 0) against clot material (not shown) to create theflow channel 1012, and the capture portions 406 accordingly exert alongitudinal force L (arrows L) against the clot material as the clottreatment device 402 is moved proximally.

The elongated inner member 1020 can be a tube or coil having inner lumenconfigured to receive the guidewire 602 for over-the-wire or rapidexchange delivery of the expandable member 1010 to the clot. The outerelongated member 1022 can be a tube or coil having a lumen configured toreceive the inner elongated member 1020 such that the inner elongatedmember 1020 and/or the outer elongated member 1022 can move relative toeach other along the longitudinal dimension of the clot treatment device402.

FIGS. 11 and 12 are detailed views of a distal portion 1011 a (FIG. 11)and a proximal portion 1011 b (FIG. 12) of the expandable member 1010 ofthe clot treatment device 402 shown in FIG. 10. Referring to FIG. 11,the distal portion 1011 a is attached to a distal end of the innerelongated member 1020 by the tip 405. The tip 405 can be blunt asdescribed above with reference to the embodiment of the clot treatmentdevice 402 shown in FIG. 4, or the tip 405 can have a tapered distalportion 1040 configured to pass through the clot as shown in FIG. 11.Additionally, the tip 405 can have a proximal opening 1042 configured toreceive the distal end of the inner elongated member 1020 and the distalend of the expandable member 1010. Referring to FIG. 12, the proximalportion 1011 b is attached to the distal end of the outer elongatedmember 1022 by a proximal hub 1030. For example, the distal and proximalportions 1011 a and 1011 b can be attached to the inner elongated member1020 and the outer elongated member 1022, respectively, using welds,adhesives, crimping or clamping forces, and/or other suitable attachmentmechanisms.

In the operation of the clot treatment device 402 shown in FIGS. 10-12,the expandable member 1010 can self-expand from the undeployed state tothe deployed state without an actuator. For example, as a deliverycatheter is drawn proximally to release the expandable member 1010, theinner elongated member 1020 can be held in place to hold the distalportion 1011 a of the expandable member 1010 distally of the clot. Asthe distal end of the delivery catheter moves proximally, the outerelongated member 1022 will slide distally as the expandable member 1010expands until the expandable member 1010 reaches its predetermineddeployed size or otherwise reaches equilibrium with the clot. In otherembodiments, the inner elongated member 1020 and/or the outer elongatedmember 1022 can be actuators that are moved proximally and/or distallyto control the radial expansion and/or the radial contraction of theexpandable member 1010.

FIGS. 13 and 14 are detailed views of the proximal and distal portions1011 b and 1011 a, respectively, of an expandable member 1010 and othercomponents of a clot treatment device 402 in accordance with anotherembodiment of the technology. In this embodiment, the clot treatmentdevice 402 has a proximal tube 1410 (FIG. 13) and an expansion element1420 having one end attached to the proximal tube 1410 and another endattached to the distal portion 1011 a (FIG. 14) of the expandable member1010. The expansion element 1420, for example, can be a coil or springthat is stretched from its normal state when the expandable member 1010is the low-profile, undeployed state inside the delivery catheter. Asthe distal portion 1011 a and then the proximal portion 1011 b of theexpandable member 1010 are released from the delivery catheter, theexpansion element 1420 contracts axially under its own stored springforce causing the expandable member 1010 to contract axially and expandradially outward. In the embodiments where the expandable member 1010 isself-expanding, the expansion element 1420 assists the expansion of theexpandable member 1010. In other embodiments, the expandable member 1010may not be self-expanding or may be inherently spring-biased into thelow-profile undeployed state, and the expansion element 1420 can haveenough stored energy when it is stretched in the low-profile undeployedstate to pull the distal portion 1011 a and the proximal portion 1011 bof the expandable member 1010 toward each other and thereby radiallyexpand the expandable member 1010.

In the foregoing embodiments, the radially extending capture portions406 provide more surface area along the device than a device that isuniformly cylindrical. Moreover, the radially extending capture portions406 extend transversely to the longitudinal dimension of the device tomore effectively transfer the axial force as the device is moved axiallyalong the vessel after deployment. Such increased surface areafacilitates the treatment and/or retrieval of a much larger portion ofthe clot 100 than is generally feasible with a uniformly cylindricaldevice. For example, in a preferred embodiment of the clot treatmentdevice 402, the device will have an external surface area between 1.5×and 6× the surface area of a uniformly cylindrical device of the samegeneral diameter of the cylindrical sections 412. In other preferredembodiments the ratio will be 2 x to 4 x.

This is advantageous particularly during retraction of the clottreatment device 402 through the clot 100. As shown in FIG. 6F, the clottreatment device 402 may become elongated as it is being withdrawnthrough the clot 100. Such elongation causes the clot material toencounter greater surface area of the clot treatment device 402 thanwould otherwise occur with a device that was only generally cylindrical,i.e., that did not incorporate radially extending portions 406.Accordingly the clot treatment device 402 is particularly adept atcapturing the maximum amount of clot material during withdrawal.

The clot treatment device 402 is intended for use in large vessels,i.e., vessels with a diameter greater than 8 mm. For example, thediameter of the pulmonary arteries typically range from 15 to 30 mmwhereas the first branches of the pulmonary arteries typically rangefrom 10 to 15 mm and the secondary and tertiary branches typically rangefrom 5 to 10 mm. At the same time, however, it is important to minimizethe size of catheter providing access to the clot 100. Accordingly, theclot treatment device 402 has a large expansion ratio. In a preferredembodiment the expansion ratio from the diameter of the cylindricalsections 412 in the collapsed state to the expanded state will bebetween 4 and 8. In another preferred embodiment the ratio will bebetween 5 and 7. The large expansion ratio also enables the formation ofa flow channel in the clot 100 that is large, e.g., on the order of 4-8mm.

The radially extending portions 406, in their fully expanded positionare intended to have a size that matches the diameter of the targetblood vessel. However, the diameters may be slightly larger than thevessel diameter so to apply greater radial force against the bloodvessel (without causing trauma) in those circumstances when it isdesirable to improve clot collection. Similarly, in those circumstanceswhere there is a concern of creating trauma on delicate blood vessels,the radially extending portions 406 may have a diameter that is smallerthan the vessel diameter. It is contemplated that different sizes of thedevice 402 will be available for selection by the user for a particularpresentation of the patient.

As for the length of the clot treatment device 402, it is known that atypical pulmonary embolism will have a length within the range betweenabout 2 em and 10 em and sometimes between about 1 em and 20 em.Accordingly, in a preferred embodiment, the clot treatment device 402will have a length that exceeds the length of the embolism so that aportion of the clot treatment device is positioned distal of the clot100 during expansion.

With regard to the delivery catheter 606, in a preferred embodiment foruse with a pulmonary embolism, the size will be around 1F-6F. Smallerdiameters will pass through the clot 100 more easily. In addition, thedelivery catheter 606 may have stiffness characteristics to assist inmaking sure the delivery catheter 606 passes through the clot in asmooth manner. Such stiffness characteristics include self expandingNitinol wire braids or stent structures that are contained within thestructure of the delivery catheter 606. The delivery catheter 606 alsohas sufficient flexibility so that it may carry the clot treatmentdevice 402 and still pass through a tortuous vessel path as describedabove starting with insertion of the delivery catheter 606 in thefemoral vein FV.

In some preferred embodiments, the method and device in accordance withthe present invention may reduce the Mean Resting Pulmonary ArteryPressure (MRPAP). Upon at least partial relief from the clot 100, MRPAPmay be reduced by about 20-50 mmHg to a normal range of 8-20 mmHg. Insome embodiments, the reduction in MRPAP may be about 25-50%. In someembodiments, the reduction in MRPAP may be about 15% to 40% and in otherembodiments between about 30% and 75%.

Such a reduction in MRPAP can occur in two steps. A first step is whenthe clot treatment device 402 is first deployed and blood flow is atleast partially restored. A second step may be when the clot treatmentdevice 402 is retracted and at least some of the clot 100 is removedfrom the vessel. A third step may be after the clot treatment device 402has been removed and the effect of the body's own processes and/orthrombolytic drugs that may have been used before, during or after theprocedure take effect upon clot that has been disrupted by the clottreatment device.

FIG. 15 is a side view of an embodiment of a guide catheter 1500 for usewith any of the foregoing embodiments of the clot treatment devices 402(not shown in FIG. 15). The guide catheter 1500 can include a shaft 1502having a sufficiently large lumen to accommodate the delivery catheter606 (FIGS. 4 and 5A). The guide catheter 1500 can further include anexpandable guide member 1510 at the distal end of the shaft 1502configured to expand radially outward to contact or nearly contact thevessel wall VW. The guide member can be formed from a permeable,radially expanding material, such as a mesh or other macroporousstructure (e.g., a braid of wires or filaments). The guide member 1510,for example, may be formed from a tubular braid of elastic orsuper-elastic filaments such as Nitinol that has been heat set into thedesired expanded shape. The permeable, radially expanding guide member1510 may have advantages over an occlusive member such as a balloon orimpermeable funnel. For example, the guide member 1510 allows asubstantial amount of blood flow BF to continue flowing through theblood vessel where therapy is being directed. In addition, the guidemember 1510 positions the shaft 1502 and delivery catheter 606 at ornear the center of the vessel. The clot treatment device 402 (not shownin FIG. 15) may also be substantially self-centering upon deployment,and the guide member 1510 may further guide the clot material capturedby the clot treatment device 402 into the shaft 1502 as the clottreatment device 402 moves into proximity of the distal end of the shaft1502. This is expected to enhance aspiration of the clot material. Forexample, in the embodiment shown in FIG. 15, the radially expandingguide member 1510 has a funnel shape adjacent the distal end of theshaft 1502 to guide thrombus material into the distal opening of theshaft 1502 where it can be more readily aspirated.

The radially expanding guide member 1510 may also be formed byconventional machining, laser cutting, electrical discharge machining(EDM) or other means known in the art to make a fenestrated, mesh orporous structure that can be affixed near the distal end of the shaft1502. In some embodiments the radially expanding guide member 1510 mayself-expand, but in other embodiments it may be actuated by an operatorusing, for example, electrical or electromechanical means. By having aporous radially expanding guide member 1510, the guide catheter 1500 maybe substantially centered within a vessel without blocking a largeportion of the flow around the catheter. In some embodiments, theradially expanding guide member 1510 may block less than about 50% ofthe flow about the catheter and in other embodiments less than about 25%of the flow. When the guide member 1510 is made with a braid offilaments (e.g. wires), it may be formed from a tubular braid. In someembodiments, the tubular braid may be formed with approximately 12 toapproximately 144 filaments, or in other embodiments from about 36 toabout 96 filaments. The pores as measured by the largest circle that canbe inscribed within an opening of the mesh may be between about 0.5 mmand 5 mm.

FIGS. 16 and 17 show additional embodiments of guide members 1610 and1710, respectively, that can be used instead of or in addition to theguide member 1510. Referring to FIGS. 15 and 16, one or both ends of thetubular braid of the guide members 1510 and 1610 may be inverted andattached to the catheter body. Referring to FIG. 17, neither end of theguide member 1710 is inverted. With the distal end inverted, itadvantageously may form a funnel adjacent the distal opening of thecatheter that may enhance clot capture and aspiration.

FIG. 18 shows an embodiment of a guide catheter 1900 having a shaft 1902and a guide member 1910 in accordance with another embodiment of thetechnology. In the embodiment shown in FIG. 18, the guide member 1910has a tapered or funnel shape, and includes a non-permeable portion 1912and a permeable portion 1914. The permeable portion 1914 can comprise aflared radially expanding mesh that has, at least in part, a tapered orfunnel shape, and the non-permeable portion 1912 may have asubstantially non-porous or otherwise non-permeable material or coatingover the mesh. Preferably, the non-permeable material is a highlyelastic material such as polyurethane, silicone, latex rubber and thelike so that it can flex with the expansion of the mesh. In someembodiments, the non-permeable material covers a proximal portion of themesh as shown in FIG. 18. The non-permeable portion 1912 may divert someflow away from the distal end of the catheter. The covering may cover aportion of the mesh to a diameter “d”. In some embodiments, the diameterd of the covering is less than about 75% of the diameter “D” of the meshfunnel. In some embodiments, the diameter d may be less than about 50%of diameter D. The concept of a non-permeable material can also beapplied to the guide catheter 1500 shown above in FIG. 15. For example,the expandable member 1510 of the guide catheter 1500 can have anon-permeable portion 1512 at the proximal portion of the expandableguide member 1510 similar to the non-permeable portion 1912 shown anddescribed with reference to FIG. 18.

FIGS. 19-27 show additional embodiments of clot treatment devices 402 inaccordance with the present technology. The embodiments of the clottreatment devices 402 shown in FIGS. 19-27 can restore blood flow andcapture clot material in a manner similar to the embodiments of the clottreatment devices 402 described above with respect to FIGS. 4-18. Theembodiments of the clot treatment devices 402 related to FIGS. 19-27 canalso be made from the same materials and be deployed in the same manneras described above with respect to FIGS. 4-18. As such, many of thefeatures, materials and benefits of the clot treatment devices 402 shownin FIGS. 4-18 are applicable to the clot treatment devices shown inFIGS. 19-27.

FIG. 19 shows an embodiment of the clot treatment device 402 thatincludes a plurality of capture elements, such as clot engagement (“CE”)members 1952. The CE members 1952 can be (a) arcuate as shown in FIG.19, (b) bent at one or more angles (e.g., 30°, 45°, 60°, 90°, 135°,etc.), and/or (c) straight (e.g., project outward along a straightline). In some embodiments, the clot treatment device 402 can include acombination of arcuate, angled and/or straight CE members. In otherembodiments, the clot treatment device 402 can include a single CEmember 1952. The CE members 1952 can be interwoven into the meshstructure of the device 402 (see FIG. 21). The CE members 1952 can alsobe bonded, soldered, welded, tied or otherwise secured to the meshstructure or mechanically interlocked with the mesh structure. As theclot treatment device 402 is unsheathed during deployment, the CEmembers 1952 can radially extend and form a heat-set shape configured topenetrate and fasten the clot to the treatment device 402. The CEmembers 1952 can accordingly define hook-like capture elements inseveral embodiments of the present technology.

The CE members 1952 can be disposed about an exterior surface of thedevice 402. For example, as shown in FIG. 19, the CE members 1952 can bearranged in one or more circumferential rows 1954 that are evenlypositioned along a longitudinal axis of the device 402. In otherembodiments, the CE members 1952 can have any suitable arrangementand/or positioning about the device (e.g., arranged in a helicalpattern, off-set rows, random, or irregular or otherwiseuneven/non-uniform spacing, etc.).

As shown in FIG. 19, the CE members 1952 can curve proximally such thata concave portion 1956 of the CE members 1952 face a proximal region 402b of the device 402. In some embodiments, the CE members 1952 can curvedistally such that a concave portion of the CE members 1952 face adistal region 402 a of the device 402 (not shown). In particularembodiments, the clot treatment device 402 includes bothdistally-curving and proximally-curving CE members.

The CE members can have a single radius of curvature or have regionswith different radii or have a complex or changing radius of curvature.For example, as shown in FIG. 20, one or more of the CE members 1952 canhave a first portion 1958 that has a first radius R and a second portion1960 (e.g., the distal region of the CE member 1952) that has a secondradius r that is smaller than the first radius R. In some embodiments,the first radius R may range from about 2 mm to about 15 mm, and thesecond radius r may range from about 0.25 mm to about 5 mm.Additionally, the CE members 1952 can have a range of arc lengths. Forexample, in some embodiments the CE members 1952 can have an arc lengthgreater than 180 degrees. In certain embodiments, the arc length can bebetween 180 degrees and 330 degrees.

FIG. 22 shows another embodiment of a CE member 2202 having a V-shapedbase 2204 that branches into a first arm 2206 a and a second arm 2206 b.The V-shaped base 2204 and/or any portion of the first and/or secondarms 2206 a, 2206 b can be interwoven into the mesh structure of theclot treatment device 402, as shown in FIGS. 24 and 25. In someembodiments, the angle a between the first and second arms 2206 a, 2206b may be between about 40 degrees and about 100 degrees. Although FIG.24 shows a plurality of such CE members 2202 disposed about a clottreatment device 402, in other embodiments the device 402 can onlyinclude a single CE member 2202.

As shown in FIG. 25, the first arm 2206 a and the second arm 2206 b canextend into a first distal portion 2208 a and a second distal portion2208 b, respectively, where the first distal portion 2208 a and thesecond distal portion 2208 b are generally arcuate. As shown in FIG. 24,in some embodiments the first distal portion 2208 a and the seconddistal portion 2208 b can be generally linear.

Referring to FIG. 26, two or more CE members can be connected to form acircumferential structure 2602 that extends around at least a portion ofa circumference of a clot treatment device 402. The device 402 caninclude one or more circumferential structures 2602 spaced along alongitudinal axis of the device. These circumferential structures 2602can allow for the CE members to flex with the mesh structure as itexpands and contracts. In some embodiments, the angle 8 formed by thecircumferential structure 2602 can be between about 40 degrees and about100 degrees.

FIG. 23 shows one embodiment of an CE member 2302 having a double-wirearcuate portion 2306. Referring to FIG. 27, in some embodiments, theclot treatment device 402 can include a plurality of CE member 1952 anda radially extended member 406 at a distal end. The radially extendedmember 406 could be a disc, balloon, screen or other clot capturemember.

Examples

Several examples of the present technology are as follows:

1. A device for treating a pulmonary embolism, comprising:

-   -   an expandable flow restoration portion; and    -   a plurality of capture elements including at least a first        capture element and a second capture element, wherein the flow        restoration portion is between the first and second capture        elements, and wherein the flow restoration portion and the        capture elements are configured to move from a low-profile        undeployed state sized to fit within a delivery catheter to a        deployed state in which the flow restoration portion has a first        cross-sectional dimension greater than that of the low-profile        state such that the flow restoration portion forms a flow        channel through the device and the capture elements project        outwardly from the flow restoration portion.

2. The device of example 1 wherein the flow restoration portion and thecapture elements comprise an expandable braided material that is heatset to have the deployed state.

3. The device of any of examples 1 and 2 wherein the flow restorationportion and the capture elements are integrally formed from a commonbraided material.

4. The device of any of examples 1-3, further comprising a plurality offlow restoration portions and the capture elements comprise a series ofradially extending capture portions, and wherein the radially extendingcapture portions are separated from each other by individual flowrestoration portions.

5. The device of example 4 wherein the flow restoration portionscomprise expandable cylindrical sections and the capture elementscomprise radially expandable disk-like capture portions of the braidedmaterial.

6. The device of example 1 wherein the flow restoration portioncomprises a radially expandable cylindrical braided material and thecapture elements comprise protuberances projecting from the flowrestoration portion.

7. The device of any of examples 1-6 wherein the flow restorationportion has an expansion ratio from the undeployed state to the deployedstate of approximately 1:4 to 1.8.

8. The device of any of examples 1-6 wherein the flow restorationportion has an expansion ratio from the undeployed state to the deployedstate of approximately 1:5 to 1.7.

9. The device of any of examples 1-8 wherein the flow restorationportion has a diameter of approximately 4-8 mm in the deployed state torestore blood flow through a pulmonary embolism.

10. The device of any of examples 1-9 wherein the flow restorationportions and the capture elements comprises a self-expanding braidedmaterial, and the capture elements comprise capture portions that have asecond diameter greater than the first cross-sectional dimension of theflow restoration portions in the deployed state.

11. The device of any of examples 1-3 and 6-9 wherein the flowrestoration portion comprises a single expandable braided tube, and thecapture elements comprise clot engagement members configured to projectfrom the flow restoration portion in the deployed state.

12. The device of example 11 wherein the clot engagement memberscomprise arcuate members that form hook-like elements projecting fromthe flow restoration portion.

13. The device of example 11 wherein the clot engagement members areformed from wires of the expandable braided tube that defines the flowrestoration portion.

14. The device of example 11 wherein the clot engagement members areformed from separate wires that project through interstices of theexpandable braided tube that defines the flow restoration portion.

15. A pulmonary embolism treatment device, comprising:

-   -   an outer elongated member having a distal end;    -   an inner elongated member within the outer elongated member,        wherein the inner elongated member and/or the outer elongated        member slides relative to the other, and wherein the inner        elongated member has a distal end; and    -   an expandable member having a proximal portion attached to the        distal end of the outer elongated member and a distal portion        attached to the distal end of the inner elongated member, the        expandable member having a flow restoration portion and a        plurality of capture elements arranged along the flow        restoration portion, wherein the flow restoration portion and        the capture elements are configured to move from a low-profile        undeployed state sized to fit within a delivery catheter to a        deployed state in which the flow restoration portion has a first        cross-sectional dimension greater than that of the low-profile        state that defines a flow channel through the device and the        capture elements project outwardly from the flow restoration        portion.

16. The pulmonary embolism treatment device of example 15 wherein theexpandable member comprises a braided material.

17. The pulmonary embolism treatment device of example 15 wherein thedevice has a plurality of flow restoration portions and the captureelements are separated by individual flow restoration portions, andwherein (a) the capture elements comprise capture portions formed from acontinuous shape-memory braided material heat-set to the deployed stateand (b) the capture portions project from the flow restoration portionsto a second cross-sectional dimension in the deployed state.

18. The pulmonary embolism treatment device of example 17 wherein theflow restoration portions comprise cylindrical portions and the firstcross-sectional dimension comprises a first diameter in the deployedstate, and the capture portions comprise disk-like projections having asecond diameter greater than the first diameter in the deployed state.

19. The pulmonary embolism treatment device of any of examples 11-18wherein the flow restoration portion(s) have an expansion ratio from theundeployed state to the deployed state from 1:4 to 1:8.

20. The pulmonary embolism treatment device of any of examples 11-18wherein the flow restoration portion(s) have an expansion ratio from theundeployed state to the deployed state from 1:5 to 1:7.

21. The pulmonary embolism treatment device of any of examples 11-20wherein the first elongated member comprises an outer tube and thesecond elongated member comprises an inner tube within the outer tube.

22. The pulmonary embolism treatment device of any of examples 11-20wherein the first elongated member comprises an outer tube and thesecond elongated member comprises a coil within the outer tube.

23. The pulmonary embolism device of any of examples 11-20 wherein thefirst elongated member comprises an outer coil and the second elongatedmember comprises an inner coil.

24. The pulmonary embolism treatment device of any of examples 11-23wherein the flow restoration portion(s) and the capture elementscomprise a self-expanding braided material.

25. The pulmonary embolism treatment device of any of examples 11-24wherein the outer elongated member is configured to slide distally withrespect to the inner elongated member to move the expansion member fromthe undeployed state to the deployed state.

26. The pulmonary embolism treatment device of any of examples 11-25,further comprising a guide catheter having a shaft with a distal end andan expandable guide member at the distal end of the shaft, wherein theshaft has a lumen configured to receive the expandable member in theundeployed state.

27. The pulmonary embolism treatment device of example 26 wherein theexpandable guide member comprises radially expandable mesh.

28. The pulmonary embolism treatment device of example 27 wherein theradially expandable mesh comprises a braided material.

29. The pulmonary embolism treatment device of any of examples 26-28wherein the expandable guide member has a funnel shape.

30. The pulmonary embolism treatment device of any of examples 26-29wherein at least a portion of the expandable guide member is permeableto allow blood to flow through the expandable guide member when theexpandable guide member is expanded.

31. The pulmonary embolism treatment device of any of examples 26-29wherein the expandable guide member has a non-permeable portion at thedistal end of the shaft and a permeable portion extending distally fromthe non-permeable portion.

32. A pulmonary embolism treatment device, comprising:

-   -   an elongated member having a distal end;    -   an expansion portion having a proximal end attached to the        distal end of the elongated member, and the expansion portion        having a distal end; and    -   an expandable member having a proximal portion attached to the        distal end of the elongated member and a distal portion attached        to the distal end of the expansion portion, the expandable        member having at least one of flow restoration portion and a        plurality of capture elements arranged such that the capture        elements are separated by individual flow restoration portion,        wherein the flow restoration portion and the capture elements        are configured to move from a low-profile undeployed state sized        to fit within a delivery catheter to a deployed state in        which (a) the flow restoration portion has a first        cross-sectional dimension greater than that of the low-profile        state that defines a flow channel through the device and (b) the        capture elements project outwardly from the flow restoration        portion, and wherein the expansion portion is stretched from a        normal state when the expandable member is in the undeployed        state such that the expansion portion is configured to axially        contract the expandable member from the undeployed state to the        deployed state.

33. A method of treating a pulmonary embolism, comprising:

-   -   delivering an embolectomy device through the heart to a        pulmonary embolism that at least partially restricts blood flow        through a pulmonary vessel, wherein the embolectomy device has a        plurality of capture elements separated by an expandable        cylindrical section;    -   deploying the embolectomy device within the pulmonary embolism        by expanding the cylindrical section into the pulmonary embolism        so that the cylindrical section forms an expanded flow channel        through the pulmonary embolism and thereby restores blood flow        through the pulmonary embolism and by expanding the capture        elements to a greater extent than the cylindrical section so        that at least a portion of the pulmonary embolism is captured        the capture elements;    -   moving the embolectomy device and at least a portion of the        pulmonary embolism along the pulmonary vessel; and    -   withdrawing the embolectomy device and at least a portion of the        pulmonary embolism from the pulmonary vessel.

34. The method of example 33 wherein deploying the embolectomy devicecomprises expanding a plurality of radial extendable capture elements ofthe embolectomy device.

35. The method of example 34, wherein at least one of the plurality ofradial extendable capture elements is expanded distal relative to thepulmonary embolism.

36. The method of example 33, further comprising applying vacuum whilewithdrawing the embolectomy device.

37. The method of example 36, wherein withdrawing the embolectomy deviceincludes urging the portion of the pulmonary embolism into a funnelcatheter.

38. The method of example 37, wherein deploying the embolectomy devicecomprises expanding the device such that a surface area of theembolectomy device expands within a range of at least 200% to 400% ofthe surface area of a uniformly cylindrical device.

39. The method of example 33 wherein deploying the embolectomy devicecomprises expanding the generally cylindrical section by 400% to 800% ofits diameter in the undeployed state.

40. The method according to and of examples 33-39 wherein deploying theembolectomy device comprises expanding a braided material into a presetshape having a plurality of radially extending disk-like captureportions that define the capture elements.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theexampled invention. Accordingly, it is to be understood that thedrawings and descriptions herein are proffered by way of example tofacilitate comprehension of the invention and should not be construed tolimit the scope thereof.

I/We claim:
 1. A system for treating a pulmonary embolism, comprising: aclot treatment device including— an expandable flow restoration portion;and a plurality of capture elements including at least a first captureelement and a second capture element, wherein the flow restorationportion is positioned between the first and second capture elements, andwherein the flow restoration portion and the capture elements areconfigured to move from a low-profile undeployed state sized to fitwithin a delivery catheter to a deployed state in which the flowrestoration portion has a cross-sectional dimension greater than that ofthe undeployed state and the capture elements project outwardly from theflow restoration portion; a guide catheter having a shaft with a distalend portion, wherein the shaft includes a lumen configured to receivethe clot treatment device in the undeployed state; and an expandableguide member at the distal end portion of the shaft, wherein theexpandable guide member is configured to guide clot material into theguide catheter as the clot treatment device is withdrawn into the guidecatheter.
 2. The system of claim 1 wherein at least a portion of theexpandable guide member is permeable to allow blood to flow through theexpandable guide member.
 3. The system of claim 1 wherein the expandableguide member comprises at least one of a self-expanding mesh structureor a self-expanding braided structure.
 4. The system of claim 1 whereinthe expandable guide member is formed from a tubular braid of elastic orsuper-elastic filaments that have been heat set to have a desiredexpanded shape.
 5. The system of claim 1 wherein, when the guidecatheter is positioned within a pulmonary vessel, the expandable guidemember is configured to expand radially outward to contact or nearlycontact the pulmonary vessel and block less than about 50% of blood flowabout the guide catheter.
 6. The system of claim 1 wherein theexpandable guide member is configured to position the shaft at or near acenter of a pulmonary vessel in which the guide catheter is positioned.7. The system of claim 1 wherein the expandable guide member has atapered or funnel shape for guiding thrombus material into a distalopening in the shaft.
 8. The system of claim 1 wherein the expandableguide member includes a permeable portion and a substantiallynon-permeable portion.
 9. The system of claim 8 wherein the expandableguide member comprises a mesh, and wherein the non-permeable portioncomprises a non-permeable coating formed on a proximal portion of themesh.
 10. The system of claim 1 wherein the expandable guide member hasa substantially non-permeable portion affixed to the distal end portionof the shaft and a permeable portion extending distally from thesubstantially non-permeable portion.
 11. The system of claim 10 whereinthe permeable portion comprises a radially expanding mesh having atapered or funnel shape, and wherein the substantially non-permeableportion comprises an elastic material.
 12. The system of claim 1 whereinthe flow restoration portion has a first longitudinal dimension and eachof the capture elements has a second longitudinal dimension, the firstlongitudinal dimension being greater than the second longitudinaldimension.
 13. A system for treating a pulmonary embolism, comprising: aclot treatment device including— an outer elongated member having adistal end; an inner elongated member within the outer elongated member,wherein the inner elongated member and the outer elongated member sliderelative to each other, and wherein the inner elongated member has adistal end; and an expandable member having a proximal portion fixed tothe distal end of the outer elongated member and a distal portion fixedto the distal end of the inner elongated member, the expandable memberhaving a flow restoration portion and a plurality of capture elementsarranged along the flow restoration portion, wherein the flowrestoration portion and the capture elements are configured to move froma low-profile undeployed state sized to fit within a delivery catheterto a deployed state in which the flow restoration portion has across-sectional dimension greater than that of the undeployed state andthe capture elements project outwardly from the flow restorationportion; a guide catheter having a shaft with a distal end portion,wherein the shaft includes a lumen configured to receive the clottreatment device in the undeployed state; and a radially expandableguide member having a first portion affixed to the distal end portion ofthe shaft and a second portion extending distally from the firstportion, wherein the guide member is configured to guide clot materialinto the guide catheter as the clot treatment device is withdrawn intothe guide catheter.
 14. The system of claim 13 wherein, when the guidemember is expanded— the guide member defines a distal opening, the firstportion has a first diameter, and the second portion has a seconddiameter greater than the first diameter.
 15. The system of claim 13wherein, when the guide catheter is positioned within a pulmonary vesseland the guide member is expanded— the first portion of the guide memberis substantially non-permeable to divert blood flow away from the distalend portion of the shaft, and the second portion of the guide member ispermeable to allow blood to flow through the guide member and around theguide catheter.
 16. The system of claim 13 wherein the flow restorationportion has a first longitudinal dimension and each of the captureelements has a second longitudinal dimension, the first longitudinaldimension being greater than the second longitudinal dimension.
 17. Asystem for treating a pulmonary embolism, comprising: a clot treatmentdevice configured to move from a low-profile undeployed state sized tofit within a delivery catheter to a deployed state, wherein the clottreatment device has a greater cross-sectional dimension in the deployedstate than in the undeployed state; a guide catheter having a shaft witha distal end, wherein the shaft includes a lumen configured to receivethe clot treatment device in the undeployed state; and an expandableguide member including a first portion affixed at or near the distal endof the shaft and a second portion extending distally from the firstportion, wherein the second portion is permeable to allow blood to flowthrough the expandable guide member when the expandable guide member isexpanded.
 18. The system of claim 17 wherein the first portion ispermeable.
 19. The system of claim 17 wherein the first portion issubstantially non-permeable.
 20. The system of claim 17 wherein thesecond portion comprises a radially expanding mesh having a tapered orfunnel shape, and wherein the first portion comprises an elasticmaterial configured to flex with expansion of the second portion.